This invention relates to a camshaft and accessory drive for an engine and more particularly to an improved camshaft and accessory drive arrangement for V-type engines.
The advantages of employing overhead camshafts for operating overhead mounted valves are well known. Although the engine performance can be improved by such arrangements, the use of overhead camshafts and the drives therefor can present certain problems, particularly when the engine must operate in a relatively confined area, as is the conventional practice in motor vehicles. That is, in addition to driving the camshaft or camshafts from the engine crankshaft, there are normally incorporated a number of accessories such as water pumps, oil pumps and the like that are also driven from the engine crankshaft. It has been generally the practice to locate all of the accessory drives at one end of the engine for simplicity and for ease of servicing. However, when all of the drives are located at one end of the engine, the positioning of the various drives for the different devices can substantially add to the length of the engine.
In connection with engines of the type described, they operated generally on the four-stroke principle. As a result, the camshaft or camshafts must be driven at one-half the speed of the crankshaft. This necessitates the provision of some form of speed reduction between the crankshaft and camshafts which can further aggravate the aforenoted problems.
Furthermore, it has been generally the practice to employ flexible transmitters for driving the camshaft or camshafts from the crankshaft. Such flexible transmitters can take the form of either belts or chains. In either event, it is also desirable to maintain a relatively short length for the flexible transmitter so as to minimize the problems in connection with stretch and/or vibrations which can occur due to changes in engine speed and the pulsations which occur in the power output. Therefore, it has also been proposed to employ a form of intermediate shaft which is driven from the engine crankshaft and which, itself, drives the camshaft or camshafts. However, such intermediate shafts further increase the complexity of the accessory drive for the engine.
All of the aforenoted problems are still further compounded when the engine is of the type having angularly related cylinder banks such as opposed or V-type engines. Obviously, the use of flexible transmitters for driving the camshafts of angularly disposed cylinder banks further magnify the aforenoted problems.
It is, therefore, a principal object of this invention to provide an improved, simplified and compact camshaft drive arrangement for an internal combustion engine.
It is a further object of this invention to provide an improved, compact camshaft drive arrangement for an internal combustion engine of the type having angularly disposed cylinder banks.
It is yet a further object of this invention to provide a camshaft and accessory drive arrangement for an internal combustion engine wherein the camshaft and accessories can be driven from one end of the engine without significantly adding to the length of the engine.
It is a further object of this invention to provide an improved, compact camshaft and accessory drive arrangement for an engine of the type having angularly disposed cylinder banks and incorporating intermediate shafts for driving the camshafts from the crankshaft.